Heretofore, an air conditioning device such as an air conditioner or an air cleaner is provided with a timer for operating the air conditioning device based on a user's intended time. For instance, in the case of an air conditioner, the user is allowed to turn on the air conditioner so that the room temperature of his/her home is set to a comfort temperature by his/her arrival time by setting the timer to turn on the air conditioner at an intended time such as 10 minutes earlier than the expected arrival time.
In a conventional air conditioning device provided with a timer, when the user wants to start an operation of the air conditioning device so that the room temperature is set to a comfort temperature by his/her arrival time, it is necessary for the user to estimate his/her arrival time before going out, and to set the timer to turn on the air conditioning device at a time slightly earlier than the estimated expected arrival time. However, when the user goes out by car, for instance, it is often the case that there is a time lag between the expected arrival time and the actual arrival time due to traffic jam or the like.
In view of the above, for instance, Patent Literature 1 discloses a technique, in which when the user receives an e-mail indicating that a preset expected arrival time is changed from the user's mobile information terminal, the preset expected arrival time is changed to operate the air conditioning device at a time earlier than the changed expected arrival time by a predetermined time.
Further, Patent Literature 2 discloses a technique, in which a navigation device for a vehicle issues an operation instruction to an air conditioning device in association with a navigation operation so as to control the operation state of the air conditioning device. More specifically, Patent Literature 2 discloses a technique, in which a navigation device sets a driving route to the place where the air conditioning device is installed, and issues, to the air conditioning device an operation instruction, taking into consideration an arrival timing at the installation place, assuming that the user drives the vehicle in accordance with the set driving route.
Further, Patent Literature 3 discloses the following technique. When the time has come to turn on an air conditioner installed at home, a query is issued to the user coming home as to whether the air conditioner is turned on. When the user chooses to turn on the air conditioner, the air conditioner is turned on. Further, when a cause of delay of the user's arrival is detected, a query is issued to the user as to whether activation of the air conditioner is stopped. When the user chooses to stop activation of the air conditioner, activation of the air conditioner is stopped.
None of the aforementioned techniques, however, is based on the premise that two or more users control an air conditioner installed at home from a place away from home. Thus, there is further room for improvement.